Device for casting metal in molds



Jan. '8, 1929.

KOLB DEVICE FOR cAshNe METAL IN mews 2 Sheets-Sheet 1 Filed Aug. 8,192'! A Inven (or flax-K Jan. 's, 1929? 1,698,441

, R. KOLB DEVICE FOR CASTING METAL IN MOLDS Filed Au '.8, 1927 2Sheets-Sheet 2.

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Patented Jan. 8, 1929 UNITED STATES 1,698,441 PATENT oFFIcE.

ROBERT KOLB, OF BERLIN, GERMAIIY.

DEVICE FOR CASTING METAL IN MOLDS.

Application filed August 8, 1927, Serial No. 211,476, and in SwedenAugust 25, 1926.

The object of the invention is to insure a perfect filling of the moldsin casting metal and at the same time to effect a good compression ofthe metal. Unless 'speclal means areresorted to, slow-flowing metalfails to fully fill out the molds and becomes porous so that imperfect,or at the best, 1mperfect castings result. The inventlon consistsin.fillin the mold and its sprue-hole With.metal, tien moving itdownward and again stopping. In stopplng the metal is then pressed intothe mold by its inertia.

In this process it is found most satisfactory to move the moldsimultaneously and to- 1 gether with the sinelting furnace, in order toprevent a premature hardemng of the metal.

The herein disclosed process and apparatus are not onl adapted forcasting of metals but fluid a loys, compositions or mnrtures. Theapparatus for carrying out the invention consists in a melting pot withan underneath outlet which is placed overa mold, the furnace beingguided perpendlcularly and locking and unlocking at the upper end of theguides.

The drawings illustrate an embodiment of the invention, whereby-.-

Fig. 1 is a view of the general arrangement of a furnace withshock-absorber, -and Fig. 2 a longitudinal section with buttercylinderand pressure-compensation-tank.

In the device as shown in Fig.1 a motor. 11, driven by a three-phasecurrent, for mstance, rotates by means of the worm 13 and the worm-wheel12 with a powerful spring 14 :wound around its-barrel. In front of thefree, front end of this spring-drum a disk 15 on shaft 18 may be shiftedlongitudinally .by moving the hand-lever 19 of the winch. This disk 15ispressed away from the front side of the spring-drum by the cylindricalspiral spring 16, and by means of a groove, grasps a key secured toshaft 18. A tappet 17 on the disk 15, after overcoming the resistance ofthe compressible spring 16 comes within the range of the revolvingspring 14 with the motor 11 running. In this position the winch isengaged and disk 15 as well as shaft 18 with the keyed-on rope-' drumparticipate in the rotary motion of the worm-wheel 13. Hereby thewirerope 21 is wound up on the barrel of the rope-drum 20, lifting theload on the ropehook 21 By moving hand-lever 19 into the off positionthe rope-drum 20 with the load suspended from hook 21 is locked by brake22 by means of its operating lever 23. The wmch is provided with anunlocking device which may also be a suitably constructed brake 22 sothat the brake-lever 23 may simultaneously serve as an unlocking lever.

The hanger .24 of the furnace 25 is suspended from the hook 21, situatedat the end of the rope, said furnace sliding-up and down by means ofshoes 39 on perpendicular rails 41 of a guide. These perpendicular gulderails 41 are securely set in foundation blocks, a shock-absorber, as,for instance, a spring-buffer 281 being interposed between the rails 41.

The furnace 25 shown in Fig. 2 is an electric resistance furnace andrests in its hanger 24 by means of supporting pins 26. It can be closedby removable hollow plates 27 with partially slanting lateral surfaces,is

provided with a cross-girder 28 underneath and is lined with refractorybricks 29. In the interior chamber melting pots 30 with underneathoutlet 31 and a mold 32 are contamed jointly in a receptacle 33-. Themold 32 is provided with a cover 34 which is preferably cast and madeintegral with the mold 32 and isonly used once and is broken up whencasting is obtained. Ingates 35 in the cover result in a sullage-piecewhen, in filhng the mold, the metal fills the ingates as well. Thepartof the receptacle in which the melting pot 30 is located is surroundedby the annular heat resistance 36 of the resistance furnace so that thispart of the receptacle is heated more, Whereas on the other hand thepart containing the mold is also heated, but to a lesser degree byradiation and convection. Two insulated current conductors 37 lead fromthe ring 36 and later ally out of the furnace, each ending in a plate 38of rectangular or other suitable shape. The plates 38 constitute thecovers of two boxes 39 which contain the springs 40 which press saidboxes against ,the two guide rails 41. The guide rails 41 are encircledby the bottoms of the boxes 39 and are .at the same time conductingrails conveying electric heating current from any desired currentsupply. I

At the bottom of the furnace on the crossgirder 28' is a piston-rod 42carrying a piston 43. Abolt 44 with a very narrow longitudinal cavity isscrewed into the piston and may, when necessary, be interchanged withanother bolt with a narrower or widercavity. The piston 43 is arrangedto move airand liquid-tight in a cylinder 45, through which thepiston-rod 42 passes, fitting tight through its cover by means of the ina foundation block of concrete as indi.

cated. A pipe-conduit 51 leads into the chamber beneath the plate 48,connecting the latter with the lower part of a tank 52. Tank'52. locatedat the side of the foundation block, is fitted, in its cover, with asuction-valve 53. The lower portion of the buffer-cylinder 47, the tank52, the pipe 51 and'the chamber under plate 48 are filled with liquid.

The invention is applied in the following manner: A block 54 of themetal to be fused is placed in the melting pot 30 whereupon the furnaceis closed and the electric current turned on. The fusing metal dripsthrough the outlet 31 onto the cover of the mold 32, flowing through theingates 35 into the mold. The size of the metal block 54 is always suchas to fill the form with a slight excess. This exccdent, together withanamount of metal corresponding to the incomplete filling out of themold, fill the ingates 35 of the cover 34, to their inner upper edgemore or less. As soon as the mold is filled as far as is necessary, theunlocking device of the winch is set in action, the furnace dropswithout the boxes 39 leaving the guide rails 41 or the current beinginterrupted. At the bottom the cylinder 45 penetrates into thebuffercylinder 47 Hereby it compresses the air in the buffer-cylinder toa pressure which opens the relief or safety-valve 50. At this pointliquid passes from the buffer-cylinder 47 into the tank 52, compressingthe air in tank 52. This causes cylinder 45 to retard its movement,while piston 43 continues to move, but slowing down in proportion as theresistance due to the passing of the charge of cylinder 45 through thecavity of bolt 44. The furnace and the mold 32 contained therein areheld up in their movement to the same degree. The energy of the masscontained inmold 32, thus released, exerts on the metal such a pressurethat it fills out the'still remaining cavities of 'the mold and thepores of the metal, whereby the ingates 35 are emptied either entirelyor partially. The winch is then set going and again hoists the furnace.Here the piston 43 first rises in cylinder 45. Then cylinder 45 islifted and drawn out of the buffer-cylinder 47, whereby liquid flowsback from the tank 52 thru the suction-valve 49, into the buffercylinder47. Finally the furnace agam reaches its upper position above theintermediate floor 55.. It is here emptied and recharged. I

Having now more fully described and ascertained the nature of myinvention and in what manner the same is to be performed, I declare thatI claim: V

1. Device for casting metal in molds, consisting in a combined movablefurnace and mold, a perpendicular guide for said movable furnace andmold, and means for locking and unlocking the furnace and mold at theupper end ofsaid guide to sustain said combined furnace and mold at theupper end of said guide and freely gravitate toward the lower end ofsaid guide, when unlocked from nace, a receptacle in which a melting potwith underneath outlet is supported over a mold, whereby the annularheat-resistanceof the furnace surrounds the part of the abovementionedreceptacle in which said melting pot is located; a perpendicular guidefor said furnace, said guide forming the currentconductor, and means forlocking and unlocking the furnace at the upperend of said guide.

4. Device according to claim 2, in which a shock-absorber is arranged atthe bottom of said furnace. A i

5. Device for casting metal in molds, embracing a furnace, movable upand down on a perpendicular guide, a piston rod, running parallel tosaid guide on the bottom of said furnace; a piston with a narrowadjustable cylindrical cavity on said piston-rod, a closed cylindersurrounding said piston, passages for the piston-rod in cover and bottomof said cylinder, a 'bufi'er-cylincler somewhat widened at the top,fitting the outer circumference of said cylinder-and located at thelower end of the furnace 'guide above referred to; and a plate closingsaid buffercylinder at bottom and provided with a suctionand asafety-valve."

I 6. Device according to claim 5, comprising a closed chamber below theplate containing the suction-V and safety-valves" and closing saidbuffer-cylinder at bottom, a tank beside said buffer-cylinder, aconnecting conduit emptying below into said tank and leadingto saidchamber below valve plate of the bufi'er-cylinderand a plate closingsaid tank at top and provided with a suction-valve,

whereby the lower portion above said valvesupporting the meltingpot inthe furnace l v plate, of the interior chamber of said bufi'er v over amold, a perpendicular guide for the cylinder, the said chamber under thevalvefurnace, a hanger on the furnace, a winchplate, said connectinconduit'and the lower above the furnace, from the load-hooks of I arefilled with liquid.

portion of the interior chamber of said tank which winch the furnace issuspended; and

an unlocking device for the winch. 15 7 Device for casting metal inmolds, con- 7 In'testiniony whereof I have affixed my sisting in amovable furnace, a melting pot signature. v with underneath outlet, amold, means for 7 ROBERT 'KOLB.

